Aquatic toboggan slides of the type outlined above are known in the art, being described for example in U.S. Pat. Nos. 1,399,469, issued Dec. 6, 1921 to Cucullu, 1,467,293 issued Sept. 4, 1923 to Matheson, and 1,497,754 issued June 17, 1924 to Howard. Equipment of the type disclosed in these patents is not to the best of applicant's knowledge currently in use in the recreational industry, and it is believed that the reasons for this are that the equipment presents a risk of injury to users which is unacceptable for present day commercial installations, it is to difficult and expensive to maintain in good working order, and its actual performance is somewhat unpredictable and largely beyond the control of the user. The objectives sought by the present applicant in the performance of his slide are similar to those sought by Cucullu, i.e. a rapid acceleration down the slide, followed by a planing over the surface of the water for a greater or lesser distance. In order to achieve this, Cucullu provides a slight upturn to the lower end of his chute so as to impart lift and a nose-up attitude to a toboggan leaving the chute. The toboggan will therefore fly through the air on leaving the chute until the action of gravity cancels the lift and causes the toboggan to fall back to water level. During this period, the nose-up attitude of the toboggan will tend to increase, because the weight of the rider will be concentrated towards the rear of the toboggan, and the air resistance to the forward movement of the toboggan will exert a turning moment about the combined centre of mass of the toboggan and rider. The net result of this is that the rear end of the toboggan will strike the water at an angle, producing the "ricocheting" action described by Cucullu. Unfortunately, the impact with the water will also tend to occur immediately beneath the point where the rider will be seated, and the resultant shock will thus be transmitted straight up the rider's spine, as well as applying considerable stress to the toboggan, which in Cucullu's slide is apparently of similar construction to traditional snow toboggans. The present applicant has experimented with the use of such toboggans on an aquatic slide, and has found that the impact with the water applies stresses which rapidly destroy a toboggan of conventional construction and are injurious to the rider.
The two remaining patents identified above both show slides which terminate at their lower ends in floating sections which are designed to discharge a toboggan level with the water surface. Although as drawn, both show end sections which are slightly upturned, it seems intended that the hinged floating end sections will dip under the combined effect of the weight of the toboggan and the reaction entailed in changing its direction as it rounds the curve at the lower end of the slide. This level discharge of the toboggan reduces the risk of injury but also probably suppresses the "ricochet" effect described by Cucullu; it is noteworthy that neither the Howard nor the Matheson patents describe such an effect. Moreover, wave effects acting on the discharge section will render the exact direction of discharge unpredictable.
As pointed out above, conventionally constructed toboggans are not really suitable for use on the type of slide with which the present invention is concerned, since they are neither strong enough nor afford sufficient protection to the rider. Moreover, they are not designed for optimum planing characteristics over water. In Canadian Pat. No. 236,089, issued Dec. 4, 1923, Matheson describes a toboggan specifically designed for aquatic use. A specially reinforced toboggan frame is covered by a watertight skin so as to provide extra rigidity and buoyancy. Whilst the extra buoyancy may be a convenience and a safety factor if the toboggan is used in deep water, the protection it affords against injury to the user is probably no better than in the case of a conventional toboggan. In particular, there is no protection against the transmission of water impact, and nothing to guard against the user's limbs contacting the slide.
In the arrangements discussed above, the slides employed utilize roller conveyors. Proposals have also been made to utilize wheeled toboggans on plain slides, although this has the disadvantages of making it difficult to streamline the bottom of the toboggan and increasing the cost of construction. Such toboggans are shown in Canadian Pat. Nos. 27,770 and 246,640 although it is not clear whether they are intended for aquatic use. Where roller conveyors are used, it is of course important to minimize frictional losses in the conveyor, and corrosion is a major problem. It is also important to provide a slide structure which minimizes the risk of injury to its users. The Howard and Matheson structures rely on engagement of wheels and rollers with the runners of the toboggan to provide lateral guidance, which carries the risk of derailment, particularly in view of the necessarily fairly light weight of the toboggans relative to that of the user, and both would be extremely hazardous in the event of a user falling off a toboggan. The Cucullu structure relies on shallow side walls for guidance but there is nothing to prevent hands or feet being trapped between a toboggan and the sides of the slide; although the structure is less hazardous than that of Howard or Matheson to an unseated rider, the wide spacing of the rollers, the shallow side walls and the roller bearing arrangements all present risks of injury. It is believed that the wide spacing of the rollers and wheels in all the structures may be intended to reduce frictional losses as well as the cost of the structure, but it will reduce the safety of the slide, increase the stresses on both rollers and toboggan, and provide a rough ride around the bottom curve.